Warhead initiation transfer link

ABSTRACT

A nose-fused warhead is provided with means for initiated detonation of the explosive charge from the rear. A detonating shock is passed through a transfer link from the nose-fuse to a booster charge at the rear of the warhead.

[56] References Cited UNITED STATES PATENTS 1,539,947 6/1925 Lukens 102/74 3,008,414 11/1961 Jasse 102/49.7 3,027,839 4/1962 Grandy et a1. 102/27 3,296,968 1/1967 Shulman et a1. 102/27 Primary Examiner-Samuel W. Engle Assistant ExaminerThomas H. Webb Attorneys Edgar J. Brower, Roy Miller and Gerald F. Baker ABSTRACT: A nose-fused warhead is provided with means for initiated detonation of the explosive charge from the rear. A detonating shock is passed through a transfer link from the nose-fuse to a booster charge at the rear of the warhead.

Patented Dec. 14, 1971 FIG. I.

FIG. 2.

BY ROY MILLER ATTORNEY.

GERALD F. BAKER AGENT.

WARIIEAD INITIATION TRANSFER LINK GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for The Government of the Unites States of Amer- 5 ica for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION Passing a detonating wave through a live explosive charge without impairing the effectiveness of the warhead, on the other hand, presents a number of problems. Not the least of these problems is the packaging of the transfer link so as to forestall premature initiation of the warhead. If the warhead is initiated at some point other than the desired rear end, then the resulting fragment velocities and distribution fall short of design expectation. Eyen ifthewarhead is not initiatedprema;

"was I0 DETAILED DESCRIPTION OF THE INVENTION Generally illustrate in FIG. 1 is a warhead 10 comprising an explosive l4 surrounding a case 12 having attached to its forward end a conventional fuze mechanism 16. An initiation transfer link 18 is positioned centrally of the explosive 14 to transfer an initiating shock from fuze 16 to the detonating boosterZO.

For a more detailed description of the transfer link, reference is now made to FIG. 2 wherein a transfer link utilizing the steel-air energy-sink configuration is shown in some detail. The link comprises an outer tubing 22 which may be of aluminum or the like of approximately 0.375 inch outside diameter with a wall thickness of approximately 0.042 (See 15 table I An inner tubing 26 is held in spaced relationship with turning 22 by means of end spacers 24. The inner tubing is preferably of a harder material such as steel and approximately 0.250 inch outside diameter with a wall thickness of 0.049 inch so as to leave a space between the two tubes of approximately 0.0l 5 inch. A mild detonating fuze (MDF) 30 is passed through the inner tube, the inside diameter of which allows for an air space 32, and the fuze os provided with end fittings 34. The spaceggma beleft filled only with air or may be filled with a low density foam type material. A number of supporting spacers 36 are placed at a one or the other or both ends of the tubes to render the fuze and the end fittings relatively immobile within the tube. The detonating fuze is preferably a five grain per foot mild detonating fuze and fitting 34 is packed l i jillhi l ll 9 9es12 s 1&

TABLE 1.DETAILS OF STEEL-AIR ENERGY-SINK CONFIGURATION FROM CENTER OUTWARD I 4130 steel tubing in annealed condition.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a plan view, partly in cross section, of a weapon incorporating the transfer link defining the present invention;

FIG. 2 is a longitudinal cross-sectional view of a preferred embodiment of the transfer link.

The second method of rear end initiation is based on the principle of impedance mismatching (See table 2). In utilizing the impedance matching approach certain primary considerations are involved. When a shock wave crosses a material boundary, an instantaneous adjustment of shock pressure occurs. The resulting conditions, after this adjustment occurs, depend largely upon the shock impedance of the two materials. If the impedances are equal or matched, the shock will move into the new medium, its peak pressure unaltered. But, if the shock impedances and materials difi'er, then the energy of the shock will be divided and additional shock waves and/or rarefactions will be generated, depending on the specific case.

If two materials of differing impedance (such as brass and aluminum) are used in the multilayer laminar assembly, then it is possible to generate destructive interference of these resulting shock can be dropped appreciably, especially if care is taken to determine and use optimum thickness values for each layer fii suete L TABLE 2.DETAILS OF IMPEDANCE MISMATCH CONFIGURATION FROM CENTER OU'IWARD Material cumulative outside radius, in.

Diameter, Expansion,

.0200 .0365 .0465 .0620 .0780 .935 .1085 .1250 .1750 in. in. 1(H

1 5gr./lt. MDF Air Brass Al Brass Al Brass A1 .350 7 2 5 gin/it. MDF Air Aluminum Brass Al .350 7 5 gr./ft. MDF Air Al Brass Air Brass Air A1 .350 2. 4 4.. 5 gin/It. MDF Air Brass Al Brass Al Air Al .360 1 5.. 5 gr./ft. MDF Air Al Brass Al Brass Air A1 360 5 6.. i Air Al Brass Al Brass Air Al .350 0 l5 grJit. MDF.

waves. In crossing such an assembly the pressure behind a Material cumulative outside radius, in.

Diameter, Expansion, 0365 0465 0620 0675 0730 1250 1750 1850 2500 in. irLXIO" Air Brass (LE. LIV 602 Silicone rubber Al 500 13. 8 A I) ir A] 500 10. 1 15 Air Aluminum .250 9.8 4 '1 h'tyrufnam A] .500 8. 3 f, Mr Steel .500 0.0 I; My 81ml" .600 0.2

figL/H. Mill 4M0 elm-l tuhlntz ln mmmilod comlltlon. lluukwoll (I hardness value M1. M. a A e Brass and aluminum are chosen for initial investigation for What is claimed is: two main reasons. Brass has a shock impedance of approxil 5 l. A warhead initiation transfer link comprising in combinamately twice that for aluminum. Both brass and aluminum could be obtained in a series of nesting-thin-walled tubing. Table 3 gives the details of construction and table 2 illustrates the column performances. Considering the tables, it is apparent that even the least effective mismatched configuration performs better than all but the very heavy steel confinement. Even so it is not until the introduction of air spaces into the cylindrical laminates that appreciable gains are made. As noted in both tables the same slight expansion after firing was produced in experiment 5. In the case of the steel confinement, over percent greater diameter was required in order to obtain the same result. The same geometry was used in experiment 6 with a two-grain per foot length of MDF and no expansion at all resulted.

From the foregoing it is obvious that l have shown two methods of constructing an initiation transfer link for use in certain types of warheads. Such initiation transfer link accomplishes the transfer of initiation from a nose located fuse to a base or rear end booster. without afi'ecting the subsequent detonation of the high explosive charge through which is passes. Although the impedance mismatch or the steel-air energy-sink method of construction produces a workable assembly for this task, in the interest of economy and simplicity of construction, the latter construction may be considered as preferred.

All of the tubing and other materials used are commercially available and require no machining to obtain the dimensions given in the table. The thin-walled tubing used as spacers is also commercially available and obtainable in a variety of materials. The assembly may be prefabricated to slip into a central aluminum-walled core of a warhead and may be hermetically sealed if desired.

tion:

an explosive material and fuze means passing through said explosive material; means for actuating said fuze means at one side of the explosive; means situated on the other side of said explosive for detonating said explosive; and said fuze being connected to said detonating means so that when said fuze is actuated a detonating shock wave is passed through the explosive to said detonating means; end fittings on said fuze means and shock attenuating means surrounding said fuze means; said shock attenuating means comprising inner and outer tubes of dissimilar metals. 2. The transfer link according to claim 1 wherein the fuze means is a low order explosive and the end fittings are filled with a higher order explosive.

3. The transfer link according to claim 2 wherein said tubes are separated by a cushioning airspace.

4. The transfer link according to claim 2 wherein said tubes are alternately of brass and aluminum.

5. The transfer link according to claim 2 wherein said tubes are alternately of steel and aluminum.

6. The transfer link according to claim 3 wherein said outer tube is of aluminum and said inner tube is of steel.

7. The transfer link according to claim 1 wherein said attenuating means comprises a plurality of alternate aluminum and brass tubes.

8. The transfer link according to claim 3 wherein one or more airspaces are provided between tubes. 

1. A warhead initiation transfer link comprising in combination: an explosive material and fuze means passing through said explosive material; means for actuating said fuze means at one side of the explosive; means situated on the other side of said explosive for detonating said explosive; and said fuze being connected to said detonating means so that when said fuze is actuated a detonating shock wave is passed through the explosive to said detonating means; end fittings On said fuze means and shock attenuating means surrounding said fuze means; said shock attenuating means comprising inner and outer tubes of dissimilar metals.
 2. The transfer link according to claim 1 wherein the fuze means is a low order explosive and the end fittings are filled with a higher order explosive.
 3. The transfer link according to claim 2 wherein said tubes are separated by a cushioning airspace.
 4. The transfer link according to claim 2 wherein said tubes are alternately of brass and aluminum.
 5. The transfer link according to claim 2 wherein said tubes are alternately of steel and aluminum.
 6. The transfer link according to claim 3 wherein said outer tube is of aluminum and said inner tube is of steel.
 7. The transfer link according to claim 1 wherein said attenuating means comprises a plurality of alternate aluminum and brass tubes.
 8. The transfer link according to claim 3 wherein one or more airspaces are provided between tubes. 